Antileak cooling fluid



anti-leak Patented es. 2, 1943 ANTILE coon mwm Leo J. Clapsadle and Leon P. .lehle, Bufialo, N. YL, assignors to Carbide and Carbon Chemicals Corporation, a corporation of New York No Drawing. Applicaton September 13, 1939, Serial N0. 294,632

Claims.

It'is particularly concerned with new and improved leakage preventive materials adapted for general use with all kinds of cooling fluids.

Cooling systems of the type employed in automobile engines are known to be quite susceptible to leakage which may arise from numerous causes. Minute crevices and solder pores may occur at the point of joining various metal parts, and become of suflicient size to cause appreciable fluid leakage. Development of cracks in the radiator cells or the numerous other seams and soldered joints is also not uncommon, and often results from road shock and vibration, corrosion or freezing of the cooling fluid. When the breaks or leakage orifices are not considered sumcient to require a major repair, attempts are usually made to remedy the situation by the addition to the cooling fluid of anti-leak materials. Many compounds and mixtures have heretofore been proposed for this purpose, and anti-leak agents have also been added to fluids of the antifreeze type as a precautionary protection against leakage which may occur during use in the cooling system. Prior known anti-leak compositions have, however, generally lacked any substantial permanence in their leak stoppage action, they have functioned satisfactorily only in water as the cooling fluid, or have not been properly effective for numerous other reasons.

Many properties are essential to a completely effective anti-leak agent in addition to the actual ability to clog or stop the leakage orifices. Ready and uniform dispersability in all cooling fluids is an important requisite, and after dispersion thickening or coagulation should not occur, which may interfere with the normal and proper circulation of the cooling solution. The particle size must also be such as to cause no blocking of the radiator cells or other fluid passages. Small crevice leaks should be effectively stopped, as well as those of a pinhole or pore type, and a sealing or bonding action is desirable to improve the permanency of leak stoppage. Chemical inertness in the leakage preventive is also important to avoid any metal corrosion, as well as the tendency to react with corrosion inhibitors or other additive materials often present in a cooling solution. Obviously the most satisfactory anti-leak isone adapted for use, and of proper function, in any type of cooling fluid, particularly those which include freezing point de pressants such as alcohols, glycols, or glycerine, to which the anti-leak material may be added in formulating an anti-freeze mixture.

It is an object of this invention to provide antileak compositions having all of the above enumerated requisite and desirable properties, and by the incorporation of said compositions in antifreeze mixturee, further to provide improved, cooling fluids having definite anti-leak properties as well as anti-freeze and non-corrosive characteristics.

We have found that certain cellulose derivatives, in particular ethers of the alkyl cellulose type and cellulose esters, have an excellent leakage preventive action in cooling fluids. Ethyl cellulose, cellulose acetate, cellulose acetobutyrate, and cellulose nitrate are representative suitable compounds which are dispersible with exceptional uniformity in a cooling fluid without tendency to coagulate or thicken. These materials are chemically inert for the purpose intended, and in very small amounts exert an effective leak stoppage action in all types of cooling fluids. Alkyl celluloses and cellulose esters are readily available commercially and any good grade of these products are satisfactory anti-leak agents.

The solubility properties of these cellulose derivatives are useful and of importance to their efiective anti-leak action. Numerous organic solvents will dissolve them, and for the purpose of this invention the required amounts of the anti-leak material are added to the cooling fluid in a concentrated solution in solvents such as glycol ethers and esters. water the cellulose derivative is reprecipitated to form a dispersion in the cooling fluid of marked stability and uniformity. In formulating these leakage preventives with a permanent anti-freeze mixture comprising glycol, glycerine or the like, a similar procedure may be followed and the concentrated solution added to the freezing point depressant, where the anti-leak component will precipitate to form an excellently stable and uniform dispersion. With a volatile type of freezing point depressant, such as methanol, ethanol or the like, the cellulose derivatives will remain in solution, and will precipitate out only when .mixed with water in the cooling system. Under any of these procedures the anti-leak compounds proposed form extremely uniform suspensions, and the results accomplished by precipitation of the anti-leak agent from a homogeneous solution are, to our knowledge, unique in the cooling fluid art.

Upon dilution with other glycols as the freezing point depressant, a.

concentration of about 0.01% to 0.10%, by weight of the undiluted glycol, of ethyl cellulose, cellulose acetate, cellulose acetobutyrate and cellulose nitrate has given excellent results. A preferred use of these new anti-leak agents is in the formulating of anti-freeze mixtures, where their addition will not interfere with, or their required action be'aflected by, corrosion inhibitors or other additive materials.

The broadest scope of the invention is intended to include many and various kinds of cooling fluids and solutions in which the compounds here disclosed constitute the essential anti-leak agents, and it should not be limited other than as defined in the appendedclaims.

We claim:

1. A cooling fluid containing an alcohol as a freezing point depressant and a leakage preventive agent composed essentially of a member of the group consisting of alkyl cellulose and .cellulose esters, in an amount'ot about 0.003% to about 0.5% by weight of the cooling fluid.

2. A cooling fluid containing a glycol as a freezing point depressant and a leakage preventive agent composed essentially of a member of the group consisting of alkyl cellulose and cellulose esters, in an amount of about 0.01% to about 0.10% by weight of the glycol.

3. A cooling fluid containing a glycol as a freezing point depressant, a metal corrosion in hibitor, and a leakage preventive agent, said agent being composed essentially of a member of the group consisting of alkyl cellulose and cellulose esters, in an amount of about 0.01% to about 0.10% by weight of the glycol.

4. Method of preventing leakage of cooling fluid in a circulatory cooling system which comprises circulating said cooling fluid with an admixture thereto of an anti-leak agent composed essentially of a compound of the group consisting 01' alkyl cellulose and cellulose esters, in an amount of about 0.003% to about 0.5% by weight of the cooling fluid.

5. A cooling fluid containing a glycol as a,

7. A cooling fluid containing a glycol as a freezing point depressant, a metal corrosion inhibitor, and a leakage preventive agent, said agent being composed essentially of cellulose acetobutyrate in an amount of about 0.01% to about 0.10% by weight of the glycol.

8. Method of preventing leakage of an alcoholcontaining cooling fluid in a circulatory cooling system which comprises circulating said cooling fluid with an admixture thereto of an anti-leak agent composed essentially of ethyl cellulose, in an amount of about 0.01% to about 0.10% by weight of the alcohol in the cooling fluid.

9. Method of preventing leakage of an alcoholcontaining cooling fluid in a circulatory cooling system which comprises circulating said cooling ing fluid with an admixture thereto of an antileak agent composed essentially of cellulose acetobutyrate, in an amount of about 0.01% to about 0.10% by weight of the alcohol in the cooling fluid.

LEO J. CLAPSADLE. LEON P. JEHIE. 

